Strait not narrow

Q: In the Ordnance Survey National Atlas of Great Britain (1986) it states that the English Channel widens at the Strait of Dover by 70 centimetres each year. Even if the figure is much smaller, surely any widening in some way affects the new tunnel. How is the widening allowed for?

A: In reference to tbe widening of the English Channel at the Strait of Dover, Ordnance Survey confirms that the figure of 70 centimetres each year represents coastal erosion, not the movement of Great Britain relative to France.

There are very minor changes to the distance between England and France, which amount to approximately 1 millimetre every ten years. This is caused by the Southeast of England sinking at a very slow rate.

When Eurotunnel and TML (the contractors) contemplated the design of the tunnel project, this fact was taken into account and 30 000 joints in the tunnel ...

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